Pests & Diseases

Integrated Pest Management (IPM) is a method of encouraging natural predators to control pests in your garden or orchard. Nature provides a balance between plant pests and the beneficial insects that control these pests. The less we do to tamper with that balance, the more likely it is to work successfully. How does it differ from organic gardening? Proponents of IPM are not opposed to the use of chemical controls, but use them only when necessary and only in amounts and with proper timing to minimize a negative effect on the beneficial bugs in the garden.

Learn to recognize the beneficials. Knowing the good bugs is important in assessing the situation in your garden.

Use preventive sprays. “Managing Pests and Disease in Your Home Orchard” is a valuable publication to help you know when and what to spray.

Use no spray before its time. Using the safest spray at the right time, only if necessary, is the essence of IPM.

Plan ahead. Planting the right plant at the right time in the right location will help you minimize problems.

Natural predators such as lacewings, leatherwing beetles, ladybird beetles, ground beetles, wasps, praying mantis and pirate bugs will control or contain most pest populations at an acceptable level, especially if trees are kept vigorous, orchard areas are kept clean of trash and weeds, and trees are well pruned to facilitate good air movement. Home orchardists have little need to completely eradicate pests.

Most insect and mite pests of fruit trees are controlled by many beneficial species of insects and mites found in the orchard. Do not spray pests unless you are certain they are present in damaging numbers or this publication suggests you do so. Unnecessary sprays reduce control provided by beneficial species and may result in added damage from pests freed from their natural controls.

Several of the most common fruit tree diseases may be controlled by using the proper fixed copper spray during the dormant season. These diseases include: bacterial canker, brown rot, coryneum blight and peach leaf curl. See individual fruit tree pages for descriptions. Be certain to follow directions on the package exactly whenever sprays are used.

Beware: some fungicide brands recommend inadequate amounts of copper for peach leaf curl. There are numerous fixed copper materials. We recommend one that contains 50% actual copper. Do not store Bordeaux from one year to the next.

How Pests, Diseases, and Hosts Fit Together

The tables, below, are brief formats designed only as guides to be used with Integrated Pest Management (IPM) and other research-based references. If one or more of these pest and disease problems are not present, do not apply preventatives. Many do not become problems until trees begin to bear.

Dormant season treatments are most important since they will not kill beneficial insects. One spray controls many orchard pests. The following tables of Orchard Pests by Season list several common home orchard pests and include information on damage, description, life cycle, and control options. More importantly, it provides information on the seasons when these pests should be addressed if they are problems in the home orchard. When damage becomes obvious, it is often too late to treat with successful results for that year.

Weeds

Weeds can have a dramatic effect on tree growth by competing for soil moisture, physical space, and nutrients. Some weeds might even have an antagonistic or allopathic effect on trees. Experiments comparing various weed control methods have demonstrated that young trees can be reduced in their growth by 1/3 to 1/2 in the first few years if weeds are allowed to compete with trees compared to treatments with no weeds.

One of the best ways to maintain the area under home orchard trees is completely weed free with an organic mulch. The mulch keeps the soil moist, reduces evaporation, and as it breaks down, it releases nutrients to the tree. It must be at least 3 inches deep to adequately control weeds and will need to be reapplied periodically to maintain that depth. Other mulches such as heavy-duty weed cloth is an alternative to organic mulches, which eliminates the need for frequent reapplication. The best weed cloth barriers will block all the light, control all the weed growth, allow water to pass through, and last 5–10 years. Another advantage is that it can be easily cleaned off of fallen leaves and fruit to prevent the spread of diseases. Mechanical cultivation with a tiller or hand hoe also works; the important thing is to keep the area free of weeds from the beginning of growth in the spring until leaf fall.

In the dormant period, it is not critical to maintain a weed free area under the trees, so cover crops or ornamentals can be grown to improve the soil or just to look nice. Mature trees can tolerate more weeds or turf or cover crops growing within their drip-line since they already have an established root system, are full sized, and don’t need to grow as much.

Conditions that favor fruit tree diseases are wetness and lack of sanitation. The Tables of Home Orchard Diseases, below, list diseases by the area of the tree that is affected by disease and includes conditions favoring the disease, name of the disease, symptoms that might be observed, and prevention tips: